PROJECT SUMMARY: Risk for opioid use disorder (OUD) often begins in adolescence and young adulthood. Engaging and retaining adolescents and young adults (collectively, ?youth?) in early, effective treatment to is critical in order to improve the life course trajectory of addiction. For adults with OUD, office-based opioid treatment (OBOT) with a collaborative care approach optimizes patient engagement and retention in care. This approach combines physician visits, nurse care management, and behavioral therapy. Collaborative care OBOT is especially promising for youth, who can receive treatment from a trusted primary care provider in the same familiar setting they receive their usual medical care. To date, however, OBOT has not been formally adapted for treating youth. The central objective of this project is to develop and pilot an OBOT model that is enhanced for youth and that is developmentally appropriate and family-centered. The project includes: (1) an analysis of Massachusetts Department of Public Health data to measure treatment patterns and outcomes among youth with OUD, thus identifying periods of high risk for loss to follow-up and drug use relapse during treatment; (2) qualitative interviews with youth, caretakers, and key informants (such as experienced OBOT providers and primary care providers of youth in areas of high OUD prevalence) to determine necessary modifications to the OBOT model for youth; and (3) a single-arm adaptive pilot study of OBOT enhanced for youth, using implementation and improvement science techniques to optimize the intervention. The Principal Investigator, Dr. Hadland, is an early career clinician-investigator with triple board certification in General Pediatrics, Adolescent Medicine, and Addiction Medicine, and prior research experience in clinical epidemiology. With this project, he seeks to enhance his skills in interventional research, focusing on developing analytic skills in advanced survival analysis and use of correlated data, acquiring foundational knowledge in intervention development, and using implementation and improvement science methodology to optimize an intervention initially designed for adults for use among youth. Dr. Hadland will conduct this research at Boston Medical Center and Boston University School of Medicine, national leaders in addiction medicine and research. The project is supported by an interdisciplinary mentorship and advisory team with expertise in advanced biostatistical analysis, qualitative research, intervention development, developmental psychology, and implementation and improvement science.